Variable load brake



May 30, 1939. l J. cANETTA ET A1.

VARI ABLE LOAD BRAKE Filed April 27, 1937 3 ySheets-Sheet 1 @ENA May 30,1939/- J. CANETTA ET A1. 2,160,211

VARI ABLE LOAD BRAKE Filed April 27, 1937 3 SheetS-Sheel1 2 INVENTORSLJOH N CAN ET TA JOHN BGROSSWEG-E BY W #ff Wt' ATTORNEY May 30, 19.39`J. CANETTA ET AL VAR I ABLE LOAD BRAKE Filed April 27, 1957 3Sheets-Sheet 3 G: man);

ORS

SWEGrE INVENT JOHN CANETTA BOHN B.GROS

@ff/ff.

ATTORNEY hm. um

Patented May 30, 1939 STATES ATET wege, Edgewood, Pa.,

assignors to The Westinghouse Air Brake Company, Wilmerding, Pa., acorporation of Pennsylvania Application April 27, 1937, seriaiN. 139,128

21 Claims.

This invention relates to variable load brakes for vehicles such asrailroad cars or trains, and has for its principal object the provisionof a variable load brake equipment, including electromagnetic meansresponsive to variations in the load carried by a car or car truck foreffecting a corresponding variation in the degree of application of thebrakes on the car or car truck.

Another object of the invention is the provision of a variable loadbrake equipment of the character indicated in the foregoing objectwherein the maximum attainable degree of brake application is limitedsubstantially in proportion to the load carried by the car.

Another object of the invention is the provision of a variable loadbrake equipment in which the maximum degree of brake application islimited to one of a plurality of certain different uniform degrees fordifferent ranges of load carried by the car.

Another object of our invention is the provision of an electromagneticdevice including voltage translating means, the output voltage of whichis varied in a novel manner.

Another object is the provision of an electromagnetic device of thecharacter indicated in the foregoing object, wherein the output voltageof the voltage translating means is Varied according to variations inthe operating condition of the car or train, for example, in accordancewith variations in load on a car or car truck.

Another object of the invention is the provision of a variable loadbrake equipment of the character indicated in the foregoing objects,wherein the electromagnetic load-responsive device may be energized froman alternating current source or from a pulsating direct current source.

The above objects and other Objects of the invention, which will be madeapparent in the subsequent description of our invention, are attained bythe provision of several illustrative embodiments of our inventiondescribed hereinafter and shown in the accompanying drawings, wherein:

Fig. 1 is a simplified diagrammatic View, with parts thereof in sectionshowing one embodiment of our invention,

Figs. 2 and 3 are plan and elevational views respectively of theconoidal cam element of the control valve device shown in Fig. 1,

Fig. 4 is a diagrammatic view showing another embodiment of my inventionemploying a different type of control valve mechanism, and

. Fig. 5 is a fragmentary diagrammatic view 6.5- illustrating apulsating direct current supply for the embodiments shown in Figs. 1 and4 instead of an alternating current supply.

Brief description of embodiment shown in Fig. 1

The embodiment shown in Fig. 1 comprises, briefly, at least one brakecylinder lil, the supply of iiuid under pressure to which is effected bya control valve device ll which may be operated locally and directly byan operator, or indirectly by remote control from a brake valve deviceI2 in the manner shown. The brake valve device I2 is operative to supplyfluid under pressure from a main reservoir i3 to a pipe, hereinaftercalled the control pipe i4, and a fluid-pressure-operated device lsubject to the pressure in the control pipe iii functions to causeoperation of control valve device il.

According to our invention there is further provided an electromagneticload-responsive device 16 and an amplifier or relay l'i illustrated as a20 three electrode type of vacuum tube amplier controlled by theload-responsive device It for supplying energizing current to a solenoidcoil I8 constituting a part of the control valve device II. Otherequipment includes a pipe I9, constantly connected to the main reservoirand hereinafter called the main reservoir pipe, a full-Wave rectifier2G, indicated as of the dry disc or copperoxide type, a source 2l ofalternating current supply, a filter including inductance coils 22 andcondensers 23 for smoothing out the pulsations in the direct currentoutput of the rectifier 2t, and a potentiometer 2t for controlling thepotential on the grid of the amplifier il, and sources of directcurrent, illustrated as batteries 25 and 26, for the filament circuitand the plate circuit, respectively, of the amplifier l'l.

Detailed 'tescriptioml of embodiment shown in Fig. 1

The brake valve device I2 is of a self-lapping type, such as describedand claimedy in Patent 2,042,112 of Ewing K. Lynn and Rankin J. Bush,effective upon operation of the operating handle 28 thereof from anormal brake release position to supply uid under pressure from the mainreservoir i3 to the control pipe i4- and establish a pressure in thecontrol pipe I4 according to the degree or extent to which the operatinghandle is moved out of its normal position into an application zone.kThe brake valve device l2 is located on the control car of a train andfunctions to control the operation of one or more control valve devicesl l associated with different brake cylinders along the length of thetrain, only one control valve device I i being shown for simplicity.

The control valve device is of the type described and claimed in thecopending application Serial No. 138,740 of John Canetta, one of thepresent joint applicants, which application was led April 24., 1937. Itis similar in construction to the brake valve device I2 and differstherefrom in having an operating shaft 3| rotated by operation of thepressure actuated device I5, having a different type of operating cam 32in the form of a conoid associated with the operating shaft 3|, and inhaving the solenoid coil I8 for adjusting the position of the conoidalcam 32 vertically along the operating shaft 3| according to variationsin the load carried on the 'car in the manner to be hereinafterdescribed in greater detail. In order to more conveniently understandour invention, a detailed description of the construction and operationof the control Valve device Il will be given.

The control valve device |I comprises a sectional casing including amain section 34 having a chamber 35 formed therein which is closed atthe side by a valve casing section 36 suitably attached in sealedrelation to the main casing section 34 and which is closed at the bottomby a pipe bracket casing section 31 also suitably attached in sealedrelation to the main casing section 34. The chamber 35, hereinaftercalled the pressure chamber, is shown as constantly connected by a pipe38 to the brake cylinder IU, it being understood that relay valves maybe provided between pressure chamber 38 and brake cylinder |8 ifdesired.

Formed in the valve section 36 is a chamber 4I which is constantlycharged with fluid under pressure, as from the main reservoir I3 throughthe main reservoir pipe i9 and a branch pipe and passage 42. A supplyvalve 43 is normally yieldingly urged into seated relation on an asso`ciated valve seat by a spring 44 to cut ofi communication between thechamber 4| and the pressure chamber 35.

Also formed in the valve section 36 is a bore 45 containing a piston 46having a chamber 41 therein. The chamber 41 is constantly connected tothe pressure chamber 35 through a port or passage 48 in the piston andalso through an axial bore 49 and a port 5| to a chamber 52 at theopposite side of the piston 46, which is constantly connected toatmosphere, as through an exhaust port and passage 53.

A pin type Valve 54, hereinafter called the release valve, is containedin the chamber 41 and is normally yieldingly biased to an unseatedposition by a spring 55 to establish communication from pressure chamber35 to atmosphere by way of passage 48, chamber 41, bore 49, port 5|,`

chamber 52 and exhaust passage 53.

Interposed in the chamber 52 between the piston 46 and a threaded plug51 screwed into the outer end of the bore 45 is a coil spring 58 whichnormally positions the piston 46 inwardly of the bore 45 and yieldinglyopposes movement of the piston outwardly of the bore 45. In the plug 51is an axial bore 59 having a smooth inner portion and a threaded outerportion. The smooth inner portion of the bore 59 receives the end of astem 6| of the piston 46 and the outer threaded portion of the bore 59receives a set screw 62 which is engaged by the outer end of the stem 6Iof the piston 46 and serves as a stop to limit the movement of thepiston 46 outwardly of the bore 45. A lock-nut 63 may be provided on theset screw 62 to prevent undesired loosening thereof.

Operation of the supply valve 4| and the release valve 54 is effected bymeans of a so-called floating lever 64 which is pivotally mountedintermediate its ends, as by a pin 65, on an actuating rod or stem 66which is slidably mounted in the casing. One end of the lever 64 haspivotally attached thereto a rod or stem B1 which extends to and engagesin a recess in the face of the supply valve 4| at the inner seated areathereof. At the opposite end of the lever 64 is mounted a roller 68which engages the inner end of the release valve 54.

The inner end of the actuating rod 66 is formed to receive and hold arelatively small ball-bearing 69 for minimizing the friction at thepoint of Contact with the cam surface of the conoidal cam element 32.

The rotary operating shaft 3| of the Valve device is suitably journaledin the main casing section 34, a portion of the shaft extending to theexterior of the casing and having iixed thereto a pinion gear 1I thatmeshes with a gear rack 12 formed on or attached to the stem 13 of apiston 14 which operates in a cylinder 15 of the pressure-actuateddevice I5. Interposed between the piston 14 and the end wall of thecylinder 15 is a spring 16 which is effective when fluid under pressureis entirely released from a chamber 11, at the opposite side of thepiston 14 and in constant communication with the control pipe I4, forshifting the piston 14 to an extreme position in the left-handdirection, thereby correspondingly rotating the rotary shaft 3| to itsnormal position.

As will be seen in Figs. l, 2 and 3, the conoidal 'cam element 32comprises a cylindrical body portion 19 and a cam portion 8| preferablyintegral with body portion 19. At the upper end of the body portion 19is a polygonal recess, shown as a square recess 82, for slidablyreceiving the inner end of the rotary shaft 3| of corresponding crosssection. A spring 83, surrounding the rotary shaft 3l and interposedbetween a flange or collar 84 xed to the shaft 3| and the upper face ofthe cam element 32, yieldingly opposes upward movement of the camelement 32 relative to the rotary shaft 3|. If desired, a collar orwasher 85 may be interposed between the spring and the upper end of thecam element 32.

As will be seen particularly in Figs. 2 and 3, the cam portion 8| of thecam element 32 has formed thereon a sloping cam surface 86 whichconnects an upper inner spiral 81 and a lower outer spiral 88. Thesloping cam surface 86 will accordingly be seen to be in reality asuccession of an infinite number of spiral line surfaces wideningoutwardly from the inner spiral line 81 to the outer spiral line 88, allof the spiral lines merging into a common vertical plane or line at theoriginating end of the spiral. The reason for the term conoidal asapplied to the cam element 32 should accordingly be apparent.

The spirals 81 and 88 may be of any desired or suitable contour but arepreferably of such contour that the actuating rod 66 is shifted in theright-hand direction, as Viewed in Fig. l, a distance which isproportional to the degree of rotary movement of the shaft 3| from itsnormal position.

With the rotary shaft 3| in its normal position, the ball-bearing 69,which is small enough to effect a substantially single point of contactwith the cam surface 86 normally engages the cam surface 86 at theoriginating end of the cam surface 8S so that, regardless of theposition of the cam element 32 vertically vwith respect to the rotaryshaft 3|, the actuating rod 55 is always returned to the same normalposition upon the return of shaft 3l to its normal position.

If the ball-bearing 59 on the end of the actuating rod 55 engages thecam surface 86 adjacent the upper spiral line 81, it will be seen theactuating rod B is shifted a certain distance assuming rotation of therotary shaft 3l through a given angle. Obviously, if the ball-bearing 59at the end of the actuating rod 66 engages the cam surface 85 adjacentthe lower spiral line 88, rotation of the rotary shaft 3| through thegiven angle will effect a greater displacement of the rod 65 in theright-hand direction. If the ball-bearing t9 at the end of the actuatingrod engages the cam surface 85 at a point intermediate the inner andouter spiral lines 8l and 88, it will be seen that the displacement ofthe actuating rod 55 in the right-hand direction for rotation of therotary shaft .3| through the given angle will be greater than that forthe spiral line 37 but less than that for the spiral line 88. Thedisplacement of actuating rod 36 in the right-hand direction forrotation of shaft 3| through a given angle thus increases as the cam 32is raised and decreases as the cam is lowered.

The position of the cam element 32 vertically relative to the rotaryshaft 3l is determined according to the degree of energization of thesolenoid coil i8. As shown, the solenoid coil i8 is l mounted ininsulated relation on the pipe bracket casing section 3l in coaxialrelation to the rotary shaft 3|, the solenoid coil controlling theposition of a plunger 89 having a stein 9|, which is secured to androtatable witnin the lower end of the cani element 32, as by aball-bearing race 92. Thus, the plunger 85 may be fixed against rotationon its axis without interfering with the free rotation of the camelement 32 by rotation of the rotary shaft 3i.

Assuming that the rotary shaft 3| is rotated through a given angle fromits normal position, and that the actuating rod 55 is correspondinglyshifted in the right-hand direction, operation of the suppiy valve 4|and release valve 54 is effected in the following manner. The spring 55is biasing the release valve 54 to unseated position is weaker than thespring 44 holding the supply valve ti seated, and consequently shiftingof the rod 5B in the right-hand direction causes the oating lever 64 topivot about its upper end in such manner that the lower end thereofshifts in the right-hand direction to seat the release valve 54 and thusto cut off communication between the pressure chamber 35 and atmosphere.Since the spring 55, opposing movement of the piston 45 outwardly of thebore 45, is stronger than the spring 44 holding the supply valve 4|seated, further movement of the actuating rod 56 in the right-handdirection after the release valve '54 is Seated causes the oating lever54 to pivot about its lower end in such manner that the upper endthereof shifts in the right-hand direction and, through the stem 5l,effects unseating of the suppy valve 4| against the force of the spring44. Fluid under pressure is accordingly supplied from the main reservoirthrough the main reservoir pipe I9, branch pipe and passage 42, chamber4|, past .the unseated valve 4 3 into the pressure chamber 35 'andthence to the brake cylinder I0. When the pressure of the fluid suppliedto the chamber 35 and the brake cylinder l0 builds up to a suicientdegree on the inner face of the piston 46, the spring 58 is overcome andthe piston 45 moves outwardly of the bore 45. Thereupon, spring 44becomes effective to shift the supply valve 43 to a seated position tocut off the further supply of fluid under pressure to the chamber 35,the release valve 54 being held seated to prevent the release of uidunder pressure from the chamber 35, due to the force exerted by thespring 44 which causes the floating lever 54 to pivot on the pin 65intermediate the ends thereof.

Ifthe rotary shaft 3| is rotated to a further extent away from itsrelease position, the supply valve 43 is again unseated to again supplyfluid under pressure to the pressure chamber 35 and brake cylinder llito increase the pressure therein, the supply of fluid under pressure tothe chamber 35 being cut off when the pressure in the chamber 35increases to a degree sufficient to overcome the spring 58 and causereseating of the supply valve 43. It will thus be seen that the pressureestablished in the pressure chainber 35 and in the brake cylinder lll isalways proportional to the degree of rotation of the shaft 3| from itsnormal position.

The maximum degree of pressure, corresponding to normal pressure in themain reservoir I3, is attained in the p-ressure chamber 35 and brakecylinder li by rotating the rotary shaft 3| to a maximum degree out ofits release position. In such case, the end of the stem 6| of the piston46 is engaged by the stop screw 62, as the piston 46 is moved outwardlyof the bore by the pressure built up in the chamber 35, before thesupply valve 43 can be returned to seated position. Thus, supply valve43 is maintained unseated and consequently the pressure from the mainreservoir equalizes into the pressure chamber 35 and brake cylinder lll.

When the rotary shaft 3| is rotated back toward its normal position froman application position, the force holding the release valve 54 seatedis relieved, and consequently the spring 55 becomes effective to unseatthe release valve 54 and thus establish communication through whichfluid under pressure is released from the pressure chamber 35 and brakecylinder l5 to atmosphere through the exhaust port 53. As the pressurein the chamber 35 reduces, spring 58 becomes effective to return thepiston 46 inwardly of the bore 45 and thus to effect reseating of therelease valve 54. If the rotary shaft 3| is again shifted a certainamount back toward its normal release position, the release valve 54 isagain unseated, to further reduce the pressure in chamber 35, thereduction of pressure in the chamber 35 and brake cylinder lo being cutolf when the pressure in the chamber 35 is reduced sufficiently so thatthe spring 58 again returns the piston 46 to a further extent inwardlyof the bore 45 to effect reseating of the release valve 54, The amountof the reduction of pressure in the chamber 35 and brake cylinder l0will thus be seen to be proportional to the degree to which the rotaryshaft 3| is returned toward its release position.

When the rotary shaft 3| is returned to its normal position, the releasevalve 54 remains unseated to reduce the pressure in the pressure chamber35 and the brake cylinder IG to atmospheric pressure since the spring 58is ineffective to shift the piston 46 a sufcient degree inwardly of thebore 45 to effect reseating of the release valve 54.

Since the degree to which the actuating rod 66 is shifted in theright-hand direction from its normal position, for a rotation of therotary shaft 3| through a given angle, increases as the cam element 32is shifted upwardly relative to the rotary shaft 3|, it will beunderstood that the pressure attained in the pressure chamber 35 andbrake cylinder l0 for rotation of the rotary shaft 3| through the givenangle will increase proportionately as the cam element 32 is raised fromthe position shown in Fig. 1.

Referring now to Fig. l, the electromagnetic load-responsive device I6comprising our invention includes an upper laminated magnetic coreportion S5, a lower laminated magnetic core portion 95, and suitablycarried in insulated relation on the upper magnetic core portion aprimary winding 9'! and a secondary winding 98. The upper core portion95 has two depending leg portions |0i and |02 and the lower core portion96 has three upwardly extending leg portions |03, |04 and |05.

The upper core portion 95 and the lower core portion 96 are suitablymounted so as to be moved toward each other or away from each other, infixed alignment to a degree proportional to the increase or decrease inload carried on a car or car truck, as for example by the device shownin Fig. 2 of Patent No. 1,670,391 to T. H. Thomas of May 22, 1928. Theprimary coil 91 surrounds the leg |0| of the upper core portion 95 andthe leg |93 of the lower core portion 96 is so located as to move in aline adjacent to the leg |0| within the primary coil 9i.

The central leg |04 of the lower core portion 96 is so located that itmoves axially within the secondary coil 98 upon relative movement of theupper and lower core portions 95 and 96. The leg |92 of the upper coreportion 95 and the leg |05 of the lower core portion 9S move in adjacentparallel lines upon relative movement of the upper and lower coreportions 95 and 95.

For the empty condition of the car or car truck, the upper core portion95 and lower core portion 96 are shifted to the maximum extent away fromeach other, as indicated by the broken line designated empty. As theload on the car or car truck increases, the upper and lower coreportions 95 and 96 are moved toward each other and with maximum or fullload on the car or car truck, the upper core portion 95 and the lowercore portion 96 are moved into the position indicated by a broken linedesignated load. For an intermediate load on the car or car truck, thecore portions 95 and 96 assume relative positions between the twopositions designated empty and load.

As indicated in Fig. l, the primary winding 91 is energized from thesource 2| of alternating current supply and a voltage is induced in thesecondary winding 98 in the manner of a transformer means.

The magnetic flux set up by excitation or energization of the primarywinding 97 traverses the core portions 95 and 96 substantially in themanner indicated by the arrows, a portion of the flux traversing thecentral leg |04 of the lower core portion 96 and a gap G between the endof the leg |04 and the upper core portion 95 while another or by-passportion of the iiux traverses the or other similar voltage translatingleg |05 of the core portion 96 vand the leg |02 of the upper coreportion 95.

The cross-sectional area of the central leg of the lower core portion 96is so designed and related to the cross-sectional areas of the legs |02and |05 that the reluctance of the magnetic path through the leg |04 andgap G decreases in percentage of maximum reluctance much more comparedto the percentage decrease of the reluctance of the magnetic paththrough the legs |95 and |02, for a given degree of movement of the coreportions toward each other. Thus, as the upper core portion 95 and thelower core portion 96 approach each other, the magnetic flux divertedthrough the path including legs |95 and |02 becomes less and less sothat the magnetic flux through the central leg |04 and gap G increases.The cross-sectional area of the central leg |04 of the lower coreportion 99 relative to the cross-sectional area of the leg |92 and |05may, therefore, readily be proportioned so that the number of ux linesor flux linkages traversing the central leg |04 of the lower coreportion 96 and the gap G increases substantially in proportion to thedegree to which the upper and lower core portions 95 and 96 approacheach other from the empty position indicated.

Since the voltage induced in a winding is directly proportional to thenumber oi' flux linkages threading the winding, it will be seen that thevoltage induced in the secondary winding 98 is substantially directlyproportional to the degree to which the two core portions 95 and 96approach eac'n other from the empty position.

In order to inhibit undesired variations in the number of flux linestraversing the central leg |04 and consequently the voltage induced inthe secondary coil 98, such as might be caused by movement of themagnetic core portions 95 and 96 relative to each other incident to jarand vibration of the car and car trucks during travei of the car ortrain along the road, a dampening ring |00 oi copper or other suitablematerial may be provided surrounding the central leg |04.

According to our invention, we employ the output voltage of thesecondary winding 99 of the electromagnetic load-responsive device i6 tocontrol the degree of energization cf the solenoid i8 of the controlvalve device so that the position of the cam element 32, vertically withrespect to the rotary shaft 3|, will vary according to the load carriedon a car or car truck.

Since it is desirable to energize the solenoid I9 by direct currentinstead of alternating current, the rectifier 20 is provided forconverting the alternating current output of the secondary winding 98 todirect current. If the power output from the secondary winding 93 issufficient, energizing current may be supplied directly from therectifier 20 to solenoid I3. However, if the power output from thesecondary winding 98 is insufficient to supply energizing current to thesolenoid I8 to a sufficient degree to overcome the force of the opposingspring 8-9, an amplifying device, such as the vacuum tube amplier i'lshown, may be employed. in such case, it is desirable to employ a filtercircuit including inductances 22 and condensers 23 to smooth out thepulsating direct current output from the rectifier 20. The potentiometer24 is provided in the output circuit from the rectier 20 to control thedegree of biasing voltage imposed on the grid of the vacuum tube amplierI'l.

The operation of the embodiment shown in Fig. l should now be apparent.Assuming that a and that a car truck is accordingly carrying itslightest load, the voltage induced in the secondary winding 98 of theelectromagnetic load-responsive device I8 is such as to energize thesolenoid I8 to a minimum degree wherein the cam element 32 is in itslowest position relative to the rotary shaft 3 I. If, now, anapplication of the brakes is effected by operation of the brake valvedevice I2, the corresponding degree of pressure established in thechamber 'l1 of the pressure-actuated device I5 correspondingly rotatesand positions the rotary shaft 3| of the control valve device II andthus establishes a certain pressure in the brake cylinder Icorresponding to the degree of movement of the handle 28 of the brakevalve device I2 out of its normal release position.

If, the load on the car or car truck is greater and the voltage outputfrom the secondary winding 98 of the electromagnetic load-responsivedevice correspondingly greater, the increased energization of thesolenoid i8 causes the plunger 89 to be shifted upwardly tocorrespondingly shift the conoidal cam element 32 upwardly from itsnormal position to a degree dependent upon and in proportion to theincrease in load. Thus, for the same degree of operative movement of theoperating handle 28 of the brake valve device l2 into its applicationzone, as assumed in the previous case,.the actuating rod 68 is shiftedin the right-hand direction a greater amount according to the slope ofthe cam surface 86, and an increased brake cylinder pressure isaccordingly established in proportion to the increase in load.

When the car or car truck is carrying its maximum load and the voltageoutput from the secondary winding 98 of the electromagneticloadresponsive device I6 is a maximum, solenoid i8 is correspondinglyenergized to a maximum degree to shift the conoidal cam element 32upwardly a maximum degree so that the ball-.bearing 58 on the end of theactuating rod E travels substantially along the line of the lower spiralline 88 on the cam surface 86 thereby effecting a maximum brake cylinderpressure for a given degree of rotary movement of the shaft 3|.

In a similar manner, if the load on a car or car truck is decreased fromthe maximum load and the voltage output from the secondary winding 98 ofthe electromagnetic load-responsive device it correspondingly reduced,the reduced energization of the solenoid I8 causes the conoidal camelement 32 to be lowered and, thus, for a given degree of rotarymovement of the shaft 3| from release position, a lower brake cylinderpressure will be effected.

Our invention is of particular advantage and utility in the case of alocomotive tender brake equipment where the load on the tender truck isconstantly reducing due to consumption of coal and water.

Since the load on the tender of the locomotive is constantly changing,it is difficult for the engineman to accurately gage the degree to whichthe brakes on the tender may be applied without causing the wheels toslide due to an excessive application of the brakes. By means of ourinvention, therefore, the degree of application of the brakes isautomatically and accurately proportioned to the load on the tendertruck. Thus the engineman may shift the operating handle 28 of the brakevalve IZ on the control car or locomotive to a certain position in theapplication Zon-e to establish a certain pressure in the control pipe|4, but the pressure 1n each brake cal 1S empty cylinder controlled by aseparate control valve device II may be different depending upon theposition of the cam element 32 as controlled by the electromagneticload-responsive device I6 associated therewith.

Regardless of the position of the cam element 32 with respect to therotary shaft 3|, the return of the operating handle 28 of the brakevalve device l2 to normal release position always effects completerelease of all the brakes, because the cam surface 8S merges into acommon line equidistant at all points from the axis of the cam element,and thus causes the return of the actuating rod t6 to the same releaseposition to effect complete release of fluid under pressure from thebrake cylinder I8.

Embodimenr shown in Fig. 4

The embodiment shown in Fig. 4 differs from the embodiment shown in Fig.l principally in the provision of a control valve mechanism III in placeof the control valve device I I and in the provision of a plurality ofcontrol relays |I2, H3, ilfi, and I|5 for controlling the operation ofthe control valve mechanism. Also an additional rectifier i i6 of thedry disc type similar to the rectifier 20 is provided which converts thealternating current supplied from the Source 2| into direct current ofsubstantially constant voltage inde-v pendent of variations in load forcontrolling the magnet valve devices of the control valve mechanism III.

The control valve mechanism I I I is illustrative of the type of controlvalve mechanism described and claimed in the copending application,Serial No. 88,098 of Ellis E. Hewitt, filed June 30, 1936, and assignedto the assignee of the present application. As illustrated, the controlvalve mechanism Iii may comprise a casing having a main valve sectionH8, a plurality of diaphragm clamping sections H9 and a magnet valvesection |28 secured together in sealing relation in any suitable manner.

Formed in the casing section II8 is a chamber |23 which is constantlycharged with fluid under pressure from a source of supply, such as themain reservoir i8, through the pipe I9. Connection between the chamber|23 and a slide valve chamber |24, to which the brake cylinder I@ isconnected as by the pipe 39, is under the control of a supply valve |25in the form of a valve piston which is normally yieldingly urged intoseated position on an associated valve seat by a spring |26 to close aport or passage |21 connecting chambers |28 and |24.

Contained in the chamber |24 and slidable on an associated valve seat isa slide valve |28, hereinafter called the release valve, which isshifted on its seat by movement of an operating stem |29 to open andclose an exhaust port or passage |3| connecting the chamber |24 toatmosphere. Formed on or attached to the stem |29 is a guide piston |32which operates in an enlarged portion of the chamber |24.

When the stem |29 is shifted in a right-hand direction from the positionshown, it first shifts the release valve |28 correspondingly to coverthe exhaust port i3| and cut off the connection between the chamber |25vtothe atmosphere, and then engages the end cf a central stem |33 on thesupply valve y which stem projects through the passage E21 into thechamber |24, to effect unseating of the supply valve |25 against theforce of the spring 26. On the reverse move-ment of the stem |28, thesupply valve is iirst seated and then the release valve |28 is shiftedto uncover the exhaust port |3|.

Shifting of the stem |29 is eifected by means of the iiud pressureforces acting on a plurality of co-aXially spaced diaphragms |35, |35,|37 and |38 of successively increasing eective pressure areas in theorder named. The largest diaphragm |38 is clamped at the peripherythereof between the casing section ||8 and one of the casing sections||9 and is suitably connected co-axially to the stem |29. The diaphragme|35,y |36, |37 and |38 are connected together, as by spoolshaped spacers|39 connected or screwed together through perforations (not shown) atthe center of the diaphragms. It will thus be seen that any unbalancedfluid pressure force exerted on one or more of the diaphragms iseffective to shift the diaphragms as a unit and thus cause shifting ofthe release valve operating stem |25.

Formed between the larger diaphragm |38 and the piston |32 is a chamber|48 which communicates with the slide valve chamber |24 through a port|49 in the piston |32. Formed between the diaphragms |38 and |37 is achamber |47 and between the diaphragme` |37 and |36 is a chamber |46.Likewise, formed between the diaphragms |35 and |35 is a chamber |45,and between the diaphragm |35 and the outside casing section ||9 is achamber |44. The chamber |44 is constantly connected by a passage |5| tothe control pipe I4 and is thus always charged with fluid under pressureat the pressure established in the control pipe |4. The supply and therelease of fluid under pressure from the chambers |45, |45 and |47 isunder the control of three magnet valve devices, respectively,designated hereafter as low magnet valve device |55, intermediate magnetvalve device |55 and high magnet valve device |57.

The low magnet valve device |55 comprises a double beat valve |6l, whichis contained in a chamber |52 constantly connected to the chamber |45through a passage |63, and an electromagnet |64 which is effective whenenergized to shift the double beat valve from an upper seated positionto a lower seated position against the force of a biasing spring |55.With the electromagnet |54 energized and the double beat valve |6|correspondingly in its'lower seated position, communication isestablished from the chamber |52 past the open upper seat of the valve|5| to an atmospheric passage |65 containing a choke fitting |57. Whenthe electromagnet |54 is deenergized, the spring |55 shifts the doublebeat valve to its upper seated position to out off the communicationjust described and to establish communicalower seat of the valve from achamber |68 which is constantly connected to the passage |5| through abranch passage |69. Thus, if the control pipe i4 is charged with Huidunder pressure, deenergization of the electromagnet |54 causes chamber|45 to be charged to the pressure of the fluid in the control pipe 4. Ifthe chamber |45 is charged with uid under pressure from the control pipe4, energization of the electromagnet |54 causes fluid under pressure tobe released from the chamber |45 to atmosphere through the choke fitting|67.

The intermediate speed magnet valve device comprises a pair ofoppositely seating valves, hereinafter called the supply valve |7| andthe release valve 72, and an electromagnet |74 for shifting the supplyvalve |7| and release valve |72 from seated and unseated positions,respectively, to unseated and seated positions, res, tively, against theforce of a biasing spring iis. When the electromagnet |74 isdefenergized the unseated release valve connects a passage |75,

chamber to an atmospheric chamber |77 which is connected to atmospherethrough a choke fitting |73. When the electromagnet |74 is energized,the release valve |72 is seated to cut off the exhaust communicationjust described and the supply valve |7| is unseated to establishcommunication therepast from `a branch passage |79, connected to thepassage |5|, to the passage |75 leading to the chamber |45 to therebyeect charging of the chamber |45 according to the pressure establishedin the control pipe i4.

The high magnet valve deviceY |57 is identical in construction to theintermediate magnet valve device |55 and comprises a pair oppcsitelyseating supply and release valves |37 and an electromagnet |34 eectivewhen energized to cause shifting of the valves from their normallyseated and unseated positions, respectively, to unseated and seatedpositions, respecagainst the force of a yielding spring lease valve |82from a passage |87, connected to the chamber |47, to a chamber |33 whichis open to atmosphere through a passage having a choke f iitting |89therein. When the electromagnet |84 the release valve |82 is shifted toseated position to close the exhaust communication for the chamber |47just described, and

the supply valve |8| is unseated to open comof the fluid as establishedin the control pipe 4. i

summarizing brieiiy, it will be seen that when the low magnet valve |55is energized and the magnet valve devices |55 and |57 are deenergized,the chambers |45, |46 and |47 will be vented to atmosphere. With all ofthe magnet valve devices |55, |55` and |57 deenergized, the chamber |45is charged with fluid under pressure from the control pipe |4 while thechambers |45 and 47 remain vented to atmosphere. With only theintermediate magnet valve device |55 enegized, chambers |45 and |465 arecharged with Iuid under pressure from the control pipe i4 while thechamber |47 remains vented to atmosphere. With the magnet valve device55 deenergized and the magnet valve devices |55 and |57 both energized,all of the chambers |45 and |47 are charged with uid under pressure fromthe control pipe I4. As previously stated, the chamber |44 is alwayscharged to the pressure in the control pipe since it is directlyconnected thereto.

The magnet valve devices |55, |55 and |57 are controlled according tothe output voltage of the secondary winding 98 of theelectromagneticload-responsive device through the medium of the controlrelays H2, H3, ||4 and M5. The relays ||2, H3, ||4, and H5 are of theretarded or slow pick-up and slow drop-out type, for a reason which willbe hereinafter made apparent, although the relay H2 may be of a typewhich picks up and drops out without a time lag or delay interval. Allof the relays H2, lis, ||4 and 5 are of the so-called voitage-responsivetype, the relays being so designed as to be operated to a picked-upposition at successively increasing voltages, respectively. For example,the relay ||2 is operatively energized, that is picked-up, at arelatively low voltage, the relay ||3 is picked-up only at a highervoltage, the relay i i4 is picked-up only at a still higher voltage, andthe relay ||5 is picked-up only at a maximum high voltage.

The windings of each of the relays ||3, |I4 and ||5 are connected acrosstwo wires |93 and |94 that are connected t0 the opposite outputterminals of the rectier 2|), which recties the alternating currentoutput from the secondary winding 98 of the electromagneticload-responsive device ll. The winding of the relay ||2 is connectedacross the wires |93 and |94 in series with a contact member o the relayI3 which is in circuit-closing position only when the relay H3 is notpicked-up.

The electromagnet |54 of the low magnet valve device |65 is connected inseries With a Contact member |92 of the relay I2, across a pair of wires|91 and |98 that are connected to opposite output terminals,respectively, of the rectifier H8.

The electromagnet |14 of the intermediate magnet Valve device |56 isconnected in series with a contact member |99 of the relay I I4 acrossthe wires I 91 and |98, the contact member |99 being in circuit-openingposition as long as the relay is not picked-up.

The electromagnet |84 of the high magnet valve device |51 is connectedin series with a contact member 28| of the relay II 5 across the Wires|91 and |98, the contact member 20| being in circuit-opening position aslong as the relay is not picked-up.

In operation, assuming that the equipment shown in Fig. 4 is conditionedas shown, that is that the main reservoir is charged with fluid at thenormal pressure carried therein, that the car or train is travelingalong the road with the brakes released, and that the electromagneticload-responsive device 6 registers an empty condition on the car or cartruck, an application of the brakes is effected by operation of thebrake valve device |2 as in the rst embodiment. As previously explained,the output voltage of the secondary winding 98 of the electromagneticloadresponsive device |5 is a minimum for an empty condition, and onlythe relay I|2 is picked-up by such minimum voltage. The contact member|92 of relay ||2 is accordingly actuated to circuitclosing position toeffect energization of the electromagnet |54 of the low magnet valvedevice |65 of the control valve mechanism |II, The winding of the relaysIIE, |I4 and II5 are subject to the output voltage from the rectier 29but, for the empty condition of the car, this voltage is not high enoughto pick up any of these relays.

It will thus be seen that since only the electromagnet |94 of the magnetvalve device |55 is energized, and the chambers |45 and |46 and |41between the diaphragms vented to atmosphere correspondingly, thediaphragms are urged in the right-hand direction by a force which isequal to the unit pressure of the fluid established in the control pipeI4, and accordingly in the chamber |44, multiplied by the effective areaof the smallest diaphragm |35.

In order to more readily comprehend the operation of the control valvemechanism I,| I, let it here be assumed that the effective pressureareas of the diaphragme |35, |35, |31 and |38 may be expressed as one,two, three and four units of area, respectively. Now, as a result of theforce of the pressure in the chamber |44 shifting the diaphragme in theright-hand direction, the release valve |28 and supply valve |25 aresuccessively operated to close off the exhaust from the chamber |24 andbrake cylinder ||J to atmosphere and to cause fluid under pressure to besupplied through the chamber |24 to the brake cylinder I0. As thepressure of the fluid supplied to the chamber |24 and brake cylinder I9builds up, there is a corresponding build-up of pressure in the chamber|48 at the right-hand side of the largest diaphragm |38 due to theconnection between the chamber |48 and chamber |24 through the port |49in the piston |32.

When the force of the pressure acting in chamber |48 over the effectivepressure area of the largest diaphragm |38 substantially balances theforce of the pressure in the chamber |44 acting in the oppositedirection on the smallest diaphragm |35, the spring |26 becomeseifective to seat the supply valve |25 to cut off the further supply offluid under pressure to the chamber |24 and brake cylinder I9. Upon thecut off of the supply of fluid under pressure to the brake cylinder, theshifting of the stem |29 backwardly is stopped so that the release valve|28 is not moved sufficiently to uncover the exhaust port |3I.

It should now be apparent that the pressure thus established in thebrake cylinder I8 will bear a certain uniform ratio to the pressureestablished in the control pipe |4, such ratio being the ratio of theeiTectiVe pressure area of the daphragm |35 to the effective pressurearea of the diaphragm |38. Accordingly, assuming that a pressure of onehundred pounds per square inch was established in the control pipe |4 byoperation of the brake valve I2, a pressure of twentyi'lve pounds persquare inch is established in the brake cylinder |0.

If "now it is desired to release the brakes, the handle of the brakevalve I2 is operated to release position to reduce the pressure in thecontrol pipe |4 and chamber |44 to atmospheric pressure. Thereupon theforce of the brake cylinder pressure acting on the diaphragm |38 in thechamber |48 shifts the stack of the diaphragms in the left-handdirection so as to move the release valve |28 correspondingly to uncoverthe exhaust port I3| and thus release fluid under pressure from thebrake cylinder. When the pressure in the chamber |44 and in the chamber|48 are again equalized at atmospheric pressure, the diaphragm and therelease valve |28 are again positioned as shown in the drawings.

-Let it now be assumed that the load on the car or car truck isincreased and that the output voltage from the secondary winding 99 ofthe electromagnetic load-responsive device |6 is correspondinglyincreased a sui'lcient degree to cause the relay I |3 to pick up but notsuciently to pick up the relays ||4 and H5. After a predeterminedinterval of time corresponding to the time lag of response of relay ||3following'the increase in voltage output from the rectifier 2|), contactmember |95 of the relay I |3 shifts to circuit-opening position toeffect deenergization of the winding of the relay H2. The purpose of thetime delay in response of the relay M3, and also 0f relays ||4 and H5,is to prevent momentary voltage fluctuations, such as might result fromthe road shocks and jars on the vehicle and without any change in load,from effecting operative energization, that is, pick-up of the relays|I3, ||4, and H5. The dampening ring |99 tends to stabilize the voltageoutput from the secondary winding to also prevent undesired pick-up ofrelays H3, H4 and H5. If the output voltage from the secondary winding98 and thus from the rectier 20 is maintained, however, at an in creasedvalue, as it is in the case of an increased load, then the continuedenergization of the winding of the relay I I3 at the increased Voltagecauses the contact member |95 to be shifted to circuit-opening positionafter the elapse of the.

predetermined interval of time.

Deenergization of the winding of the relay H2 results in shifting of thecontact member |92 of the relay I I2 to circuit-opening position andthus interruption of the circuit for energizing the electromagnet |64 ofthe low magnet valve device I55. As a result, the control pipe I4 andpassage I5I is connected to the chamber |45.

If now, an application of the brakes is subsequently initiated byoperation of the brake valve I2 and a chosen pressure, such as onehundred pounds per square inch., is established in the control pipe I4,both of the chambers |44 and |45 are simultaneously charged to thepressure in the control pipe I4. Since the pressure of the fluid onopposite sides of the smallest diaphragm is thus balanced, it will beapparent that the force urging the stack of diaphragms in the right-handdiirection is that resulting from the pressure in the chamber |45 actingover the effected pressure area of the diaphragm |36. Operation of therelease valve |28 and supply valve |25 is accordingly effected, as inthe previous instance, to cause build-up of fluid under pressure in thechambers |24 and |48 and in the brake cylinder I0. In this case,however, the pressure established in the brake cylinder for the samechosen pressure of one hundred pounds per square inch in the controlpipe I4 will be higher than in the previous instance and will be inratio to the pressure established in the control pipe as the effectivepressure area of the diaphragm |36 is to the effective pressure area ofthe diaphragm I 38. On the basis of the assumed eITective pressure areaof these diaphragms of two and four units of area, respectively, it willbe seen that the pressure established in the brake cylinder in this caseis one-half of that established in the control pipe I4, or fty poundsper square inch.

Release of the brakes is effected, as in the previous instance, byreturning the handle of the brake valve I2 to release position torestore the pressure in the control pipe I4 and chambers |44 and |45 toatmospheric pressure, whereupon pressure in the brake cylinder I0 isreduced to atmospheric pressure in the manner previously described.

Assuming now that the load on the car or car truck is still furtherincreased and that the output voltage from the secondary winding 98 ofthe electromagnetic load-responsive device I6 correspondingly increasessuiciently to cause pick-up of the relay I |4 without however, pickingup the relay I5, it will be seen that after a time delay of response ofrelay H4, shifting of contact member |89 to circuit-closing position,effects energization of electromagnet I 14 of intermediate magnet valvedevice |56.

When an application of the brakes is initiated by operation of the brakevalve i2 and the control pipe |4 is charged to a chosen pressure, thechambers |44, |45 and |46 will accordingly be charged to the pressure inthe control pipe I4. Thus, since the iiuid pressure forces on oppositesides of the two diaphragms |35 and |36 are balanced, it is the forceexerted on the diaphragm |31 by the fluid under pressure in the chamber|46 which determines the degree of brake cylinder pressure established.On the basis of a ratio between the areas of the diaphragms I 31 and |38of three to four as previously assumed, it will be seen that for a onehundred pound pressure in the control pipe I4, a pressure ofseventy-five pounds is established in the brake cylinder Ill.

If the car or car truck carries maximum load,

and the output voltage from the secondary winding 98 is thussufficiently high to operatively energize, that is pick-up the relay II5, then contact member 20| of the relay |55 is shifted tocircuit-closing position to elect energization of the electromagnet |84of the high magnet valve device |51 so that upon charging of the controlpipe I4, all of the chambers |44, |45, |46 and |41 are charged withfluid at the pressure in the control pipe I4. In this case, the fluidpressures on opposite sides of the diaphragms |35, |36 and |31 arebalanced and the force of the uid pressure in chamber |41 acting on oneface of diaphragm |38 determines the degree of pressure established inthe brake cylinder. Obviously, in this case, a pressure equivalent tothat in the chamber |41 and in the control pipe I4 must be establishedin the brake cylinder I and chamber |48 before cut-off of the supply offluid under pressure to the brake cylinder can be eifected. Therefore,for a pressure of one hundred pounds per square inch in the control pipeI4, a pressure of one hundred pounds per square inch will be built up inthe brake cylinder I0.

It will thus be apparent that the control valve mechanism III controlsthe ratio between the pressure established in the control pipe I4 andthat established in the brake cylinder III depending upon the loadcarried by the car or car truck. It will likewise be apparent, that inthe case of variations of load while running along the road as in thecase of the locomotive tender, the magnet valve devices |55, |56 and |51are correspondingly conditioned so that when the control pipe I4 ischarged with fluid under pressure to initiate an application of thebrakes, the actual brake cylinder pressure established will bearsuccessively lower ratios to' a chosen pressure established in thecontrol pipe as the load on the car or car truck reduces.

Embodiment shown in Fig. 5

In Fig. 5, is shown the manner in which either of the equipment shown inFig. l and Fig. 4 may be operated from a source of direct current supplyinstead of from an alternating current supply. As shown fragmentarily inFig. 5, the primary winding S1 of the electromagnetic loadresponsivedevice I6 is energized by a pulsating direct current, the pulsatingdirect current being produced by means of a vibrator or makeand-breakswitch 2H of well known construction connected in series with theprimary winding 91 across the terminals of the direct current source ofsupply 2|0.

As indicated diagrammatically, the vibrator 2H may comprise anelectromagnet winding 2|2 effective, when energized, to shift a movablecontact member 2|3 out of engagement with a fixed or stationary contactmember 2M against the force of a resisting spring 2I5. The separation ofthe contact members 253 and 2I4 interrupts the energizing circuit forwinding 2I2 and thus the magnetic force pulling the contact member 2|3away from the contact member 2|4 is released and the spring 2I5 becomeseffective to reengage the contact member 2I3 with the contact member2I4. Upon reengagement of contact members 2I3 and 2I4, the electromagnetwinding 2I2 is again energized to cause the contact member 2I3 to pullaway from the contact member 2 I4 and the cycle repeated. The circuitthrough the primary winding 91 of the electromagnetic load-responsivedevice I6 from the source 2IEI of direct current supply being undercontrol of the vibrator 2II is accordingly alternately closed andopened, and primary winding 91 is energized by a pulsating directcurrent. Thus the flux linking the primary coil 91 with the secondarycoil 98 of the electromagnetic load-responsive device I6 is increasedand decreased alternately so as to induce an alternat ing-currentvoltage in the secondary winding 98.

Application of invention to a train brake equipment The variousembodiments of our invention hereinbefore described are, as intimated,readily applicable in the control of the brake equipment for a train ofcars either of the articulated or usual non-articulated type. In suchcase, the source 2| of alternating current supply may be located on acontrol car, such as the locomotive, and the primary winding 91 of eachelectromagnetic load-responsive device connected across a pair of trainwires 2I8 and 2I9 in the manner shown in Fig. 1.

Similarly, the pressure-actuated device, corresponding to thepressure-actuated device I5, for each control valve device II, isconnected to the control pipe I4 and the supply of uid under pressurefor the brake cylinder III through each control valve device II isthrough a branch pipe corresponding to the branch pipe 42.

In longer trains, however, it is desirable to provide a local supplyreservoir at intervals along the length of the train whereby animmediate and adequate supply of pressure for the brake cylinders isavailable instead of relying on a single main reservoir pipe I9 in themanner shown. Furthermore, the control valve device II need notnecessarily supply fluid under pressure directly to the brake cylinderbut may control the supply of fluid under pressure to relay valvedevices which in turn control the supply of vfluid under pressure fromthe local supply reservoirs to the brake cylinders in a manner Wellknown to those skilled in the art.

It will be understood that the manner of charging the control pipe I4 ismerely illustrative, it being understood that any other suitable mannerfor charging the control pipe may be em ployed, for example, a pluralityof electropneumatic valve mechanisms at intervals along the length ofthe train or a plurality of automatic valves such as a standard triplevalve controlled by reduction in a train or brake pipe pressure.

Summary summarizing, it will be seen that the present inventioncomprises a vehicle brake equipment including an electromagnetic orvoltage translating device having a primary and a secondary coil and tworelatively movable magnetic core elements, associated with the primaryand secondary coils, and moved relative to each other according to avariable operating condition of the vehicle such as the load on thevehicle, the core elements being so constructed and arranged that thevoltage induced in the secondary coil of the voltage translating devicevaries in accordance with the variable operating condition of thevehicle. While our invention is of particular utility in connection witha variable load type of brake equipment, it will be apparent that thevoltage translating device which we have provided is adapted for otherapplications and for control in accordance With any variable operatingcondition, not merely the load on a vehicle. As shown in Fig. of thedrawings, the primary coil of the voltage translating device may beenergized by a pulsating direct current instead of an alternatingcurrent as in the other embodiments shown.

It will also be seen that the present invention includes novelcombinations of elements for effecting control of two different forms ofbrake control valve devices.

While we have shown and described only several embodiments of ourinvention it will be apparent that various omissions, additions or modincations may be made in the illustrated embodiments without departingfrom the spirit of our invention. It is, therefore, not our intention tolimit the scope of our invention except as it is necessitated by thescope of the prior art.

Having now described our invention, what We claim as new and desire tosecure by Letters Patent, is:

l. In a vehicle brake equipment, in combination, a pair of inductivelycoupled coils, one of which has a substantially constant alternatingcurrent voltage impressed thereon and the other of which has a voltageinduced therein upon energization of the said one coil, means forvarying the flux coupling the two coils, without varying the eiectivealternating current voltage impressed on said one coil to cause thevoltage induced in the said other coil to vary according to a variableoperating condition of the vehicle, and means controlled according tothe voltage induced in said other coil for correspondingly controllingthe degree of application of the brakes.

2. In a vehicle brake equipment, in combination, a pair of inductivelycoupled coils, one of which has a substantially constant alternatingcurrent voltage impressed thereon and the other of which has a voltageinduced therein upon energization of the said one coil, means forvarying the flux coupling the two coils, without varying the effectivealternating current voltage impressed on said one coil, to cause thevoltage induced in the said other coil to vary according to the load onthe vehicle, and means controlled according to the voltage induced inthe said other' coil for correspondingly controlling the degree ofapplication of the brakes.

3. In a vehicle brake equipment, in combination, a pair of inductivelycoupled coils, one of which has a voltage induced therein uponenergization of the other, magnetic core means asso ciated with saidcoils, said coils and said core means being movable to dierent positionswith respect to each other according to variations in a variableoperating condition of the vehicle for causing the voltage induced inthe said one coil to correspond to the variable operating condition, andmeans controlled according to the voltage induced in the said one coilfor correspondingly controlling the degree of application of the brakes.

4.. In a vehicle brake equipment, in combination, a primary coil, asecondary coil inductively coupled to the said primary coil and having avoltage induced therein upon energization of the primary coil, movablemagnetic core means for varying the magnetic flux linkage between theprimary and secondary coils and accordingly the voltage induced in thesecondary coil, and electroresponsive means controlled. according to thevoltage induced in the said secondary coil for controlling the degree ofapplication of the brakes.

5. In a vehicle brake equipment, a primary coil, a secondary coilinductively coupled to the said primary coil and having a voltageinduced therein upon energization of the primary coil, movable magneticcore means associated with said primary and said secondary coils and soconstructed and arranged as to vary the magnetic flux linkage betweenthe primary and secondary coils upon movement of the magnetic core meansaccording to a variable operating condition of the vehicle so that thevoltage induced in the secondary coil corresponds to the variableoperating condition, and electroresponsive means controlled according tothe voltage induced in said secondary coil for controlling the degree ofapplication of the brakes.

6. In a vehicle brake equipment, a primary coil, a secondary coilinductively coupled to the said primary coil and having a voltageinduced therein upon energization of the primary coil, relativelymovable magnetic core elements associated with the said coils and soconstructed and arranged as to vary the magnetic ux linkage between theprimary and secondary coils in accordance with the relative positions ofthe core elements and thereby correspondingly varying the voltageinduced in the secondary coil, and electroresponsive means controlledaccording to variations in the voltage induced in the secondary coil forcontrolling the degree of application of the brakes.

7. In a vehicle brake equipment, a primary coil, a secondary coilinductively coupled to said primary coil and having a voltage inducedtherein upon energization of the primary coil, two movable magnetic coreelements associated with said coils and having different relativepositions corresponding to the load on a vehicle, said core elementsbeing so constructed and arranged that the magnetic fiux linking theprimary and secondary coils for the different relative positions of thecore elements causes a voltage to be induced in the secondary coil whichis in accordance with the load on the vehicle, and electroresponsivemeans controlled according to the voltage induced in the said secondarycoil for controlling the degree of application of the brakes.

8. In a vehicle brake equipment, in combination, a primary coil, asecondary coil inductively coupled to the primary coil and having avoltage induced therein upon energization of the primary coil, analternating current source for energizing the said primary coil at asubstantially constant voltage, magnetic core means associated with andmovable relative to the said coils in such manner as to effect variationof the voltage induced in the secondary coil in accordance with avariable operating condition of the vehicle, and electroresponsive meanscontrolled according to the voltage induced in the secondary coil forcontrolling the degree of the brake application.

9. In a vehicle brake equipment, electroresponsive means for controllingthe degree of brake application, a source of alternating current, asource of direct current, a primary coil constantly energized by currentsupplied from said alternating current source, a secondary coilinductively coupled to the primary coil and having a voltage inducedtherein upon energization of the primary coil, magnetic core meansassociated with said coils and movable relative thereto in such manneras to cause the voltage induced in the secondary coil to besubstantially in accordance with a variable operating condition of thevehicle, and means controlled according to the voltage induced in thesaid secondary coil for controlling the supply of current from saiddirect current source to said electroresponsive means.

10. In a vehicle brake equipment, in combination, electroresponsivemeans energizable to varying degrees to correspondingly vary the degreeof a brake application, a primary coil, a secondary coil inductivelycoupled to the primary coil and having a voltage induced therein uponenergization of the primary coil, magnetic core means associated withsaid coils and movable in such manner as to cause the voltage induced inthe said secondary coil to correspond in degree to a variable operatingcondition of the vehicle, and means controlled according to the voltageinduced in the said secondary coil for correspondingly controlling thedegree of current supplied to the said electroresponsive means.

1l. In a vehicle brake equipment, in combination, a primary coil, asecondary coil inductively coupled to the primary coil and having avoltage induced therein upon energization of the primary coil, magneticcore means associated with said coils and movable in such manner as tocause the voltage induced in the said secondary coil to correspondsubstantially in degree to a variable operating condition of thevehicle, a rectifier for converting the alternating current output fromthe said secondary coil to direct current, and electroresponsive meanscontrolled according to the direct current output from said rectier forcontrolling the degree of a brake application.

12. A vehicle brake equipment comprising in combination, a primary coil,a secondary coil inductively coupled to the primary coil and having avoltage induced therein upon energization of the primary coil, twocooperating magnetic core elements associated with the primary andsecondary coils and shiitable to dierent positions relative to eachother to vary the magnetic flux linking the two coils and thus to varythe voltage induced in the said secondary coil according to a variableoperating condition of the vehicle, and means associated with one ofsaid core elements for inhibiting rapid unsustained variations in themagnetic flux linking the primary and secondary coils.

13. In a vehicle brake equipment, in combination, a brake cylinder, amanually operated element, means operative in response to the operationof the manually operated element to establish a iiuid pressure in thebrake cylinder according to the degree of movement of the manuallyoperated element away from a normal position thereof, electroresponsivemeans for varying the response of the said last means to a givenoperative movement of the manually operated element to thereby causedifferent brake cylinder pressures to be established for a givenoperative movement of the manually operated element from its normalposition, a voltage translating means having relatively movable partsvariously positioned in response to variations in a variable operatingcondition of the vehicle for causing the voltage output of saidtranslating means to correspond substantially to the variable operatingcondition of the vehicle, and means controlled according to the voltageoutput of the translating means for controlling the saidelectroresponsive means.

14. In a variable load brake equipment for a car or train, incombination, a brake cylinder, a normally uncharged pipe chargeable withfluid at different pressures, means operative in response to thepressure in said pipe for establishing a pressure in the brake cylinderhaving only a limited number of certain different fixed ratios to thepressure in said pipe, and means responsive to the load on a car forcontrolling said last means to cause it to establish different ones ofsaid fixed ratios between the brake cylinder pressure and the pressurein said pipe.

15. In a vehicle brake equipment, in combination, a brake cylinder, anormally uncharged pipe chargeable with fluid at different pressures,means including a plurality of electroresponsive means effective uponthe charging of the said pipe to a given pressure to cause one of aplurality of different pressures to be established in the brake cylinderdependent upon which of the said plurality of electroresponsive means isenergized or deenergized, and means controlled according tothe load onthe vehicle for selectively controlling the energization of saidelectroresponsive means.

16. In a variable load brake equipment for a vehicle or train, incombination, a brake cylinder, a normally uncharged pipe chargeable withfluid at different pressures, means including a plurality ofelectroresponsive means effective upon the charging of said pipe to agiven pressure to cause one of a plurality of different pressures to beestablished in the brake cylinder dependent upon which of the saidplurality of electroresponsive means is energized or deenergized, meansfor supplying a voltage in accordance with the load on a vehicle, and aplurality of voltage-responsive relays responsive to different voltagesrespectively and controlled according to the voltage supplied by saidlast means for selectively controlling the said electroresponsive means.

17. In a variable load brake equipment for a vehicle or train, incombination, a brake cylinder, a normally uncharged pipe chargeable withfluid at different pressures, means including a plurality ofelectroresponsive means effective upon the charging of said pipe to agiven pressure to cause one of a plurality of different pressures to beestablished in the brake cylinder dependent upon Which of the saidplurality of electroresponsive means is energized or deenergized, meansfor supplying a voltage in accordance With the load on a vehicle, and aplurality of voltage-responsive relays responsive to different voltagesrespectively and controlled according to the voltage supplied by saidlast means for selectively controlling the said electroresponsive means,and means for delaying operative response of said relays for preventingundesired energization or deenergization of said electroresponsive meansupon a rapid unsustained variation in the voltage as supplied from thesaid voltage supply means.

18. In a variable load brake equipment for a vehicle or train, incombination, a brake cylinder, a normally uncharged pipe chargeable withiiuid at different pressures, means including a plurality ofelectroresponsive means effective upon the charging of said pipe to agiven pressure to cause one of a plurality of different pressures to beestablished in the brake cylinder dependent upon Which o1" the saidplurality of electroresponsive means are energized or deenergized,voltage translating means including a primary coil and a secondary coil,means responsive to the load on the vehicle for causing the voltageinduced in the secondary coil to vary in accordance with the load on thevehicle, and a plurality of separate means responsive to differentvoltages, respectively, as supplied from the said secondary coil forselectively controlling energization of the said electroresponsivemeans.

19. In a vehicle brake equipment, in combination, a primary coil, asecondary coil inductively coupled to the primary coil and having avoltage induced therein upon energization of the primary coil, a sourceof direct current, a circuit including said primary coil and source ofdirect current, means for alternately closing and opening said circuitto cause energization of the primary coil by a pulsating direct current,magnetic core means associated with the primary and secondary coils andmovable relative thereto in such manner as to cause the voltage inducedin the secondary coil to correspond substantially to a variableoperating condition of the vehicle, and electroresponsive meanscontrolled in accordance With the voltage induced in the said secondarycoil for controlling the degree of application of the brakes.

20. In a variable load brake equipment for a vehicle or train, incombination, a brake cylinder, a normally uncharged pipe chargeable withfluid at different pressures, means including a plurality ofelectroresponsive means effective upon the charging of said pipe to agiven pressure to cause one of a plurality of different pressures to beestablished in the brake cylinder dependent upon which of the saidplurality of electroresponsive means is energized or deenergized, meansfor supplying a voltage in accordance With a variable operatingcondition of the vehicle, and a plurality of voltage-responsive relaysresponsive to different voltages respectively and controlled accordingto the voltage supplied by said last means for selectively controllingthe said electroresponsive means.

21. In a variable load brake equipment for a vehicle or train, incombination, a brake cylinder, a normally uncharged pipe chargeable withfluid at different pressures, means includingva plurality ofelectroresponsive means effective upon the charging of said pipe to agiven pressure to cause one of a plurality of different pressures to beestablished in the brake cylinder dependent upon which of the saidplurality of electroresponsive means is energized or deenergized, meansfor supplying a voltage in accordance with a variable operatingcondition of the vehicle, a plurality of voltage-responsive relaysresponsive to diiTerent voltages respectively and controlled accordingto the voltage supplied by said last means for selectively controllingthe said electroresponsive means, and means for delaying operativeresponse of said relays for preventing undesired energization ordeenergization of said electroresponsive means upon a rapid unsustainedvariation in the voltage as supplied from the said voltage supply means.

JOHN CANETTA. JOI-IN B. GROSSWEGE.

